1. Field
The present invention relates to an electronic device, and more particularly, to a stack structure comprising an epitaxial graphene, a method of forming the stack structure, and an electronic device including the stack structure.
2. Description of the Related Art
Graphene is a hexagonal single-layer structure formed of carbon atoms. Graphene is chemically very stable, and has characteristics of a semi-metal in which a conduction band and a valence band are overlapped with only at one point, that is, at a Dirac point. Also, graphene shows 2-dimensional ballistic transport. A 2-dimensional ballistic transport of a charge in a medium, means that a charge is transported in a medium without resistance due to scattering. Accordingly, the mobility of charges in graphene is very high. In addition, graphene has a current density of 100 times or greater than copper, that is, about 108 A/cm2.
Due to these characteristics of graphene, research has been conducted to use graphene in various electronic devices. However, due to the difficulty of the process of manufacturing graphene, it is not easy to manufacture electronic devices including graphene structures. In detail, for example, graphene is manufactured using an exfoliation method. In the exfoliation method, single crystal graphite is bonded on a top surface of an insulating layer, and a portion of graphite, that is, graphene, is attached on the insulating layer via the Van der Waals' force therebetween. However, when using this method, it is difficult to adjust the number, position, and width of graphene layers, since the method basically expects a coincidence, and it is also difficult to obtain a large-surface graphene layer. Alternatively, a growth method of growing a graphene layer on a compound single crystal substrate has been suggested; however, the compound single crystal substrate is expensive, and it is difficult to manufacture a large-surface compound single crystal substrate. In addition, the type of the compound single crystal substrate on which a graphene layer can be grown is very limited, and it is not easy to apply the compound single crystal substrate to most manufacturing processes of electronic devices.